Field of the Invention
The present invention relates generally to power management and cooling in computer equipment.
Background of the Related Art
A data center is a facility where computer equipment and related infrastructure are consolidated for centralized operation and management. Computer equipment may be interconnected in a datacenter to produce large, powerful computer systems that are capable of meeting the computing requirements of entities that store and process large amounts of data, such as corporations, web hosting services, and Internet search engines. A data center may house any number of racks, with each rack capable of holding numerous modules of computer equipment. The computer equipment typically includes a large number of rack-mounted servers along with supporting equipment, such as switches, power supplies, network communications interfaces, environmental controls, and security devices. These devices are typically mounted in racks in a compact, high-density configuration to make efficient use of space while providing physical access and enabling the circulation of cool air.
Two important aspects of operating a datacenter are the management of power consumed by the equipment and the provision of adequate cooling. The large amount of rack-mounted computer equipment in a datacenter may collectively consume a large quantity of power and generate a large amount of heat. The infrastructure provided in a datacenter is intended to support these significant power and cooling demands. For example, the datacenter may provide electrical utilities with the capacity to power a large volume of rack-mounted computer equipment, and a cooling system capable of removing the large quantity of heat generated by the rack-mounted computer equipment. The cooling system in many installations will also include a particular arrangement of equipment racks into alternating hot aisles and cold aisles, and a computer room air conditioner (“CRAC”) capable of supplying chilled air to the cold aisles. Meanwhile, chassis-mounted blower modules help remove heat from the racks and exhaust the heated air into the hot aisles.
The servers commonly used in datacenters are becoming more challenging to cool, as a result of parameters such as higher component packaging densities, sharper variations in server workload, and a general demand to reduce energy consumption within cooling subsystems. Power management in a server or among a group of servers addresses the balance between providing greater amounts of cooling and driving up energy consumption. Providing more cooling than necessary will consume more energy than necessary. Conversely, too little cooling can cause a temperature threshold to be exceeded and invoke performance-reducing power reduction measures. Exceeding such a temperature threshold may cause the server to perform at a lower performance level in order to reduce the heat generated and avoid component damage or data integrity issues. In order to avoid exceeding such a temperature threshold even when a component suddenly goes from an idle state to maximum workload, systems typically keep critical components well below the allowable temperature thresholds to provide an additional safety margin. Of course, maintaining components at lower operating temperatures requires the consumption of additional power.